CROATIAN SOCIETY OF CLINICAL EMBRYOLOGISTS – GUIDELINES ON THE EPIDEMIOLOGICAL FRAMEWORK FOR THE IMPLEMENTATION OF MEDICALLY ASSISTED REPRODUCTION (MAR) PROCEDURES DURING THE COVID-19 PANDEMIC REGARDING THE SAFETY OF PATIENTS AND MEDICAL HEALTH WORKERS

Due to the high virulence of the SARS-CoV-2 virus, the infection rate in the community has led to a state of pandemic, leading to the introduction of new emergency measures all over the world. With the aim of controlling and preventing the SARS-CoV-2 viral epidemic, the health institutions performing medically assisted reproduction (MAR) suspended any new MAR treatments in order to reduce the burden on the health care system and implement current social distancing recommendations. Considering the favorable epidemiological situation in Croatia, our perspective is that it is time to conceive, plan and bring forth guidelines for restarting work in MAR centres, taking into account the selection of patients and organization of good laboratory and clinical practices with emphasis on the safety of patients and health workers. In regard to epidemiological knowledge, it is important to establish the reorganization of work in MAR centres including epidemiological measures of reducing unnecessary stays in closed spaces, the usage of protective gear by patients and health workers and disinfection of the working spaces and equipment

Models for telomere Q-PNA-FISH labeling.

<p>A) Single-stranded breaks along telomere G-rich strand and dissociation of stretches of the same strand could cause incomplete labeling of G-rich strand with PNA probe. B) Condensed telomere structures on metaphase chromosomes contribute to less effective labeling by Q-PNA-FISH.</p

Estimates of the parameter <i>α</i>.

<p>Estimates of the parameter <i>α</i>.</p

Results of the one-sided z-tests for comparison <i>a</i>-parameters.

<p>Results of the one-sided z-tests for comparison <i>a</i>-parameters.</p

Example and analysis of one metaphase spread from MJ90 cells, PD 52.

<p>A) Merged image after <i>in situ</i> hybridization of telomere Cy3-PNA probe (red) on metaphase chromosomes stained with DAPI (blue). B) Distribution of relative differences between sister telomere signals in percentages for a given metaphase.</p

Telomeres of hTERTMJ90 cells, PD 127.

<p>A) Southern blot analysis of MJ90hTERT and MJ90 cells. <i>M</i> =  molecular weight marker. B) Q-PNA-FISH of MJ90hTERT cells. Merged image after <i>in situ</i> hybridization of telomere Cy3-PNA probe (red) on metaphase chromosomes stained with DAPI (blue). C) Distribution of telomere fluorescence signal relative differences between sister telomeres in MJ90hTERT cells.</p

Arithmetic means of absolute differences with respect to longer telomere signals in MJ90 cells at PD32.

<p>Arithmetic means of absolute differences with respect to longer telomere signals in MJ90 cells at PD32.</p

Estimated regression model for PD 32 sample: regression line (blue), 95% CIs of expected values of <i>Y</i> given <i>x</i> (ordinates of the green lines), and 95% CIs of the response values of <i>Y</i> given <i>x</i> (ordinates of the red lines).

<p>Estimated regression model for PD 32 sample: regression line (blue), 95% CIs of expected values of <i>Y</i> given <i>x</i> (ordinates of the green lines), and 95% CIs of the response values of <i>Y</i> given <i>x</i> (ordinates of the red lines).</p

Schematic representation of telomere replication and subsequent Q-PNA-FISH labeling and analysis.

<p>For a 10∼1,5% of the longer sister length. Q-PNA-FISH labeling generates much larger differences among signal intensities. On average these differences are 20% which corresponds to about 2000 base pairs. We used measured signals for further mathematical and statistical modeling.</p